Use of portable X-ray fluorescence in the analysis of surficial sediments in the exploration of hydrothermal vents on the Southwest Indian Ridge

Hydrothermal plumes released from the eruption of sea floor hydrothermal fluids contain large amounts of oreforming materials. They precipitate within certain distances from the hydrothermal vent. Six surficial sediment samples from the Southwest Indian Ridge（SWIR） were analyzed by a portable X-ray fluorescence（PXRF） analyzer on board to find a favorable method fast and efficient enough for sea floor sulfide sediment geochemical exploration. These sediments were sampled near, at a moderate distance from, or far away from hydrothermal vents. The results demonstrate that the PXRF is effective in determining the enrichment characteristics of the oreforming elements in the calcareous sediments from the mid-ocean ridge. Sediment samples（〉40 mesh） have high levels of elemental copper, zinc, iron, and manganese, and levels of these elements in sediments finer than 40 mesh are lower and relatively stable. This may be due to relatively high levels of basalt debris/glass in the coarse sediments, which are consistent with the results obtained by microscopic observation. The results also show clear zoning of elements copper, zinc, arsenic, iron, and manganese in the surficial sediments around the hydrothermal vent. Sediments near the vent show relatively high content of the ore-forming elements and either high ratios of copper to iron content and zinc to iron content or high ratios of copper to manganese content and zinc to manganese content. These findings show that the content of the ore-forming elements in the sediments around hydrothermal vents are mainly influenced by the distance of sediments to the vent, rather than grain size. In this way, the PXRF analysis of surface sediment geochemistry is found to satisfy the requirements of recognition geochemical anomaly in mid-ocean ridge sediments. Sediments with diameters finer than 40 mesh should be used as analytical samples in the geochemical exploration for hydrothermal vents on mid-oceanic ridges. The results concerning copper, zinc, arsenic, iron, and manganese and their ratio features can be used as indicators in sediment geochemical exploration of seafloor sulfides.

Geochemical analysis of marine sediments using fused glass disc by X-ray fluorescence spectrometry

A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard （for the trace elements）. The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% （n=12）.

X-ray fluorescence spectrometry determination of open-hearth furnace slag by pressed powder briquetting

A rapid analysis method of determining content of eight compounds of open-hearth furnace slag was developed using X-ray fluorescence spectrometry and pressed powder briquettes. Matrix effect was corrected using theoretical alpha coefficient. Grains-size effect was eliminated by optimized sample preparation technique parameters. Mineral effect was corrected with standard curve of specially made standard samples. The analysis results of TiO2, TFe, SiO2, MgO, Al2O3, CaO, MnO and P2O5 in slag samples showed that both precision and accuracy are comparable with that of chemical method.

Determination of Content of Eight Elements in Metal Coating Smeared on Waste Plastics by X-ray Fluorescence Spectrometry

X-ray fluorescence spectrometry was used to detect the content of eight elements in metal coating smeared on waste plastics,and effects of sample cups,elements in plastic substrate,and interaction of elements in metal coating on detection results were analyzed. The results show that the RSD of the method used to detect element content in the metal coating smeared on the waste plastics ranged from 0.008% to 0.044%; the determination range of the eight elements was 0.002%-52.0%,and their detection limit ranged from 0.0002% to 0.0008%. The determination results of X-ray fluorescence spectrometry were consistent with that of ICP-AES. The method can provide technical support for the determination of damage and pollution caused by metal coating smeared on waste plastics.

Quantitative Analysis of FeMo Alloys by X-Ray Fluorescence Spectrometry

A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.

Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy(LIBS),as a fast on-line analysis technology,has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants,the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present.In this paper,we propose a novel x-ray fluorescence(XRF) assisted LIBS method for high repeatability analysis of coal quality,which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal,but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements.With the combination of elemental lines in LIBS and XRF spectra,the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal.Quantitative analysis results show that the relative standard deviation(RSD) of C is 0.15%,the RSDs of other elements are less than 4%,and the standard deviations of calorific value,ash content,sulfur content and volatile matter are 0.11 MJ kg,0.17%,0.79% and 0.41%respectively,indicating that the method has good repeatability in determination of coal quality.This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.

Application of a Portable XRF Spectrometer for <i>In-Situ</i>and Nondestructive Investigation of Pigments in Two 15th Century Icons

A simple portable X-Ray Fluorescence (XRF) spectrometer was successfully used for in-situ and nondestructive identification of the painting materials in two 15th century icons from the Onufri Museum in Beart, Albania. The spectrometer is based on a low power X-ray tube, a thermoelectrically cooled Si PIN detector and the spectrum acquisition system. It was assembled and adjusted at our laboratory for the investigation of the icons. A small number of pigments were clearly identified by X-Ray Fluorescence (XRF) measurements in both icons. This includes Lead white for the white color, gold and yellow ochre for the yellow color, red lead, cinnabar and red ochre for the red color, as well as cooper based pigments for the green color. At the same time, the investigation raised some new questions that need further investigations by the use of additional analytical techniques. The results show that in both icons are used similar pigments, which are in accordance with the Byzantine icon painting tradition.

A TOTAL CONTENT X—RAY FLUORESCENCE METHOD FOR COPPER PROSPECTING

A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of a Cu deposit. Applications of the technique in Northeast China are presented.

生态环境监测工作中应用AAS/AFS和XRF法测定土壤重金属数据质量评价

当前我国生态环境监测工作中,测定土壤重金属等无机元素全量所采用的标准方法主要为原子吸收光谱法(AAS)、原子荧光光谱法(AFS)和波长色散X射线荧光光谱法(WDXRF)等。为掌握AAS、AFS和WDXRF等方法测试结果的有效性和可比性,本文选取了20个来自全国不同区域、不同类型的实际土壤样品,通过盲样方式插入国家土壤环境监测任务样品批次中,分发至3~5个实验室,采用AAS/AFS、WDXRF和便携式X射线荧光光谱法(p-XRF)平行测定Cr、Ni、Cu、Zn、As、Hg、Cd、Pb、V和Mn十个元素全量。结果表明:元素含量水平分布均匀(在≤1.0、1.0~2.0、2.0~10.0及>10.0水平均有分布);85%以上样品Cr、Ni、Cu、Zn和Pb元素WDXRF方法的实验室间相对偏差(RD)更理想,60%样品As元素AFS方法的RD更优,元素含量对WDXRF方法的RD有更明显影响。总体上,AAS/AFS和WDXRF两类方法实验室间精密度控制水平均较高,WDXRF法更理想。进一步分析AAS/AFS和WDXRF方法间平行性(以这两类方法测试结果的相对偏差RD’进行评价),Cr、Ni、Cu和Zn元素的RD’基本低于20%,As和Pb元素80%以上的RD’低于20%,Pearson相关性和线性关系分析表明这两类方法有较高的可比性;另外,Cr、Ni、Cu、Zn、Pb和As元素的p-XRF与AAS/AFS方法测试结果也有较理想的可比性。本研究认为,AAS/AFS和WDXRF两类方法具有等同测试效果,实际监测工作中Cd、Hg等含量较低元素宜选择检出限较低的AAS/AFS法;因WDXRF方法的前处理过程简单易控,大批量土壤分析中使用该方法更加高效,在特定实验条件下p-XRF方法也有可接受的定量效果。

便携式X射线荧光光谱测定车用三元催化剂中铂钯铑

采用粉末样品杯法制样,建立了用便携式X射线荧光光谱对车用三元催化剂中贵金属铑(Rh)、钯(Pd)、铂(Pt)含量进行实时、在线定量分析的方法。比较了6种实验室常用样品薄膜对测试结果的影响,通过透光率试验发现各样品薄膜对能量高于5.4keV(24 Cr以后元素)的X射线的透光率为100%,样品膜越薄其分析灵敏度就越好,实验时选用厚度为4.0μm的Ploy-4样品膜;研究了元素谱线之间的干扰重叠校正,采用背景扫描与α经验系数法相结合的方法进行基体校正,避免了因基体的变化对测定准确度的影响;讨论了X射线荧光光谱法中检出限的计算方法,采用Pt、Pd、Rh含量较小样品多次测试结果的标准偏差来计算检出限,铑、钯、铂的检出限分别为14.04μg/g、18.17μg/g、8.40μg/g。对一种车用三元催化剂粉末样品进行精密度考察,相对标准偏差(RSD)控制在4.0%之内;对8个车用三元催化剂实际样品进行分析,经与电感耦合等离子体原子发射光谱法(ICP-AES)进行比对,测定结果基本一致,相对误差在10.0%之内,方法的准确度能够满足车用三元催化剂回收要求。

高光谱技术无损鉴定壁画颜料之研究——以西藏拉萨大昭寺壁画为例

本文利用高光谱技术分析了两幅模拟壁画,通过比较模拟壁画颜料与标准颜料光谱曲线的形状特征及其一阶导数特征峰和计算颜料光谱匹配度,有效准确地甄别出蓝铜矿、孔雀石、雌黄、藤黄、雄黄、铅丹和朱砂,但无法判别胭脂。同时,高光谱技术鉴定出的西藏拉萨大昭寺转经廊壁画中蓝铜矿、孔雀石、铅丹和朱砂颜料,与便携式X射线荧光元素成分结果一致。本研究结果表明高光谱技术可无损与准确地鉴定中国古代颜料,与便携式X射线荧光元素成分分析相结合,是壁画现场无损快速分析的重要手段。

水分对于便携式X射线荧光光谱仪测定土壤中元素含量的影响

便携式X射线荧光光谱法(PXRF)是测定土壤中元素含量的一种方法,但由于土壤中的水分含量会影响采用该方法的测试结果,因此需要对土壤中水分的影响进行实证研究。实验采用便携式X射线荧光光谱仪(PXRF)对不同含水量的土壤样品中有益元素(K、Ca、Fe、Mn)和有害元素(Cr、Ni、Zn、Pb、Cu)进行测试,探讨水分对于测试结果的影响,并将结果与电感耦合等离子体原子发射光谱法(ICP-AES)结果作比较。结果表明,PXRF对于不同元素的敏感性不同,对于土壤样品中含量较大的K、Ca、Fe、Mn元素来说,样品中水分含量越大,元素含量的PXRF检测结果越小,且水分对于这几种元素的PXRF检测结果存在显著性影响,在含水量分别不超过0、0.20、0.10、0.10mL/g时,PXRF检测结果与ICP-AES测试值之间无显著差异;对于Cr、Ni、Zn、Pb、Cu几种含量较低的元素,PXRF检测结果受水分影响相对较小,表现为先下降后基本不变,其中Cr、Zn、Pb元素检测结果在含水量分别不超过0.20、0、0.10mL/g时,PXRF检测值与ICP-AES结果无显著差异;Cu元素的ICP-AES结果显著高于所有的PXRF测试值,且在含水量为0~0.10mL/g之间,PXRF检测值无显著差异,之后显著下降,但受水分的影响不再显著;Ni元素含量的PXRF检测结果基本不受水分的影响,但含水量在0~0.15mL/g时,Ni元素的PXRF检测值显著高于ICP-AES结果。因此采用便携式X射线荧光光谱仪进行土壤中重金属的现场快速测定时,应注意土壤的水分条件。

手持式X射线荧光光谱仪在牙科非贵金属无损检测中的应用

采用手持式X射线荧光光谱(PXRF)法对两种口腔常用标准品和4种常用牙科非贵金属的主要元素进行无损检测,并且与原子吸收光谱(AAS)法进行比较。对YSBC18604–08钛铁标准品的主要元素Fe,Ti,Al,Mn和YSBC15343–2008不锈钢标准品的主要元素Fe,Cr,Mn以及4种已知元素含量的牙科钴铬支架(Co,Cr,Mo,W)、镍铬合金金属桥(Ni,Cr,Mo)、齿科钴铬烤瓷合金(Co,Cr,Mo,W)、镍基铸造合金(Ni,Cr,Cu,Sn)进行分析检测。对含量较高(>20%)的元素,其测定结果的相对标准偏差均小于0.8%(n=9),含量小于10%的元素其测定结果的相对标准偏差均小于4%(n=9)。不锈钢标准品YSBC15343–2008和钛铁标准品YSBC18604–08各元素测定结果与标称值基本一致,相对偏差在0.025%~2.54%范围内。PXRF法和AAS法对原材料中主要元素的测定结果基本一致,均与标称含量相符合。PXRF法对成品及原材料的分析不需要破坏试样,分析速度快,准确度高,重现性好,能同时检测多种元素,满足日常分析要求。

A New Discovery of Ag-Pb-Zn Mineralization via Modern Portable Analytical Technology and Stream Sediment Data Processing Methods in Dajiacuo Area, Western Tibet(China)

Tibet, which is rich in mineral resources, is a treasure trove for geological explorers. However, prospecting work has been slow, especially in the western part, due to the precipitous terrain, changeable climate and low access. Hence, modern advanced field analytical technology and effective data processing methods play significant roles in rapid and efficient exploration in Tibet. In this paper, spectrum-area fractal modeling and portable X-ray fluorescence analysis(pXRFA) were used to identify and verify geochemical anomalies associated with Ag-Pb-Zn mineralization based on a stream-sediment dataset of 39 elements in the Dajiacuo-Xurucuo region of western Tibet. First, staged factor analysis(SFA) was used to obtain the Ag-Pb-Zn-Cd geochemical assemblage. Second, the first-factor pattern obtained using SFA was dissociated by a spectrum-area(S-A) fractal model and a digital elevation model(DEM)-based geochemical model(DGM) was constructed. Finally, the sections of Ag, Cd, Pb, and Zn were obtained using pXRFA. The results show that Ag-Pb-Zn-Cd enrichment zones were mostly located around the contact belt of volcanic rocks and intrusions, or along SE-NW trending faults. Considering the variable terrain and catchment basin, the extension of long axes of Ag-Pb-Zn-Cd anomalies into higher elevation areas that are favorable for Ag-Pb-Zn mineralization should be investigated. Anomaly maps created with the aid of a DGM show promising potential for mineralization in the Dajiacuo-Xurucuo region, and abundant Ag-Pb-Zn mineralization was identified with the assistance of pXRFA in the source areas for the geochemical anomalies in the Dajiacuo. We conclude that SFA and the S-A fractal model constitute a valid tool to identify or verify geochemical anomalies in areas of low-density stream-sediment sampling. The pXRFA can accurately determine the source of geochemical anomalies and improve anomaly verification efficiency.

土壤中铁元素对铬元素p-XRF测定准确度的影响与校正

便携式X射线荧光光谱仪(p-XRF)能够快速检测土壤中的铬元素,但由于土壤成分复杂、基体效应不明,导致其检测准确度较低。铁元素作为土壤基体中的主量元素,在不同类型土壤中含量变化范围大,是影响铬元素p-XRF测定准确度的主要元素之一,深入研究铁元素对铬元素荧光强度的影响有助于提高p-XRF测定土壤中铬元素的准确度。本文以人工配置的铬-铁土壤样品研究铬元素荧光强度与铬元素含量和铁元素含量的变化关系,采用经验公式校正铁元素对铬元素p-XRF分析准确度的影响。结果表明:土壤样品中的铁元素含量固定不变时,铬元素的含量与其相应的特征X射线荧光强度呈线性变化,相关系数均在0.9990以上,且铬元素荧光强度的增长速率随着土壤中铁元素含量的增加而增大;另外通过对同一铬含量、不同铁含量土壤样品的研究,验证了铁元素对铬元素的荧光增强效应,并发现该增强效应还与铁、铬元素的相互作用有关。结合铬、铁元素基体效应研究结果,本文建立了铁元素对铬元素p-XRF测定的校正方程式,相比于普通的线性回归,该方法的相关系数从0.9011提高到了0.9986,硅藻土样品的p-XRF分析平均相对误差从21.94%下降至2.52%,实际土壤样品的p-XRF分析平均相对误差从51.02%下降至5.21%。

化学在考古学中的跨学科应用:使用手持式X射线荧光光谱仪鉴定唐代血经主要元素成分

采用手持式X射线荧光光谱仪(pXRF)现场无损对照检测了南京大学博物馆收藏的国家一级文物敦煌莫高窟出土唐人写本《大方便佛报恩经残卷》朱书和血书字迹主要重金属元素成分。通过检测字迹中汞元素和铁元素相对含量多少,结合颜色深浅,鉴定血书中的浅色字迹含有较为丰富的铁元素,应为血液成分所带来。我们首先使用pXRF测试了古代常用红色颜料主要成分含汞元素的朱砂粉、含铁元素的三氧化二铁、两者50:50和99:1混合物浸迹以及动物干血迹中汞元素和铁元素的含量,对照X射线能谱仪(EDX)结果证明pXRF对朱砂中汞元素和铁元素都有很好的检测响应,即使血迹中微量的铁元素也能很清晰地检测出来。我们随后使用pXRF对馆藏的朱书和血书中的字迹对照颜色进行元素相对含量分析,结果显示朱书的字迹普遍颜色较深,主要成分为朱砂;血书中大部分颜色较浅的字迹主要成分为血和朱砂的混合物,而血书中少部分颜色较深的字迹则是由朱砂为主要成分的颜料修补所致。本文为现场无损鉴定成书时间较长的文物血经提供了一种较为可靠的原位无损检测化学方法,可以作为大学化学知识跨学科应用的一个课堂讲解例子。

便携式X射线荧光光谱(PXRF)法同时测定氧化锌富集物中锌、铁、氯、镉、砷

氧化锌富集物的进口能弥补我国锌矿资源的不足,但要求ZnO>50%、Fe<10%、Cl<8%、Cd<0.25%、As<0.6%。目前常采用YS/T 1171.1~10—2017《再生锌原料化学分析方法》检测氧化锌富集物中锌、铁、氯、镉、砷含量,该系列检测方法均需要繁琐的湿法样品前处理,测量过程较为冗长,不能满足氧化锌富集物大量进口时快速通关的需求。建立了采用便携式X射线荧光光谱(PXRF)法同时测定氧化锌富集物中锌、铁、氯、镉、砷的方法。采用YS/T 1171.3—2017和YS/T 1171.5—2017方法对氧化锌富集物样品进行定值,然后选取21个含量具有梯度的氧化锌富集物样品作为校准样品,建立起各元素X射线荧光强度值与含量的校准曲线。各曲线相关系数在0.8164~0.9999,方法检出限为0.013%~2.0%,各元素的相对标准偏差(RSD,n=11)均小于0.05%。与化学方法检测氧化锌富集物样品对比,结果基本一致。方法能应用到口岸现场进口氧化锌富集物快速筛查,检测一个样品仅需1 min,极大地加快了进口氧化锌富集物通关速度。

对比等离子发射光谱法/原子荧光法探讨便携式X射线荧光光谱法在测定土壤重金属中的应用

2015年5月29日至31日,针对韶关市某工业园区周边土壤布设4个点位,使用便携式X射线荧光测定仪,现场测定了Cr、Cu、Pb、Zn、Ni和As六种重金属含量,同时采集相同土壤样品带回实验室,使用电感耦合等离子发射光谱仪/双道原子荧光光度计分析土壤中重金属含量。通过对比来分析便携式X射线荧光测定仪在测定土壤重金属中的应用。

高精度X射线荧光法测定土壤中的重金属

为满足土壤环境质量应急监测需求,便携式X射线荧光法测定土壤得到了广泛应用。采用高精度便携式X射线荧光光谱仪(HDXRF)对不同标准土壤中Cu、Pb、Zn、Cd、Cr、Ni、As等7种元素进行测定,结合AAS/AFS等实验室仪器的测定结果,建立线性回归方程,比较分析HDXRF法快速测定土壤重金属的准确性、可靠性,旨在为环境应急监测应有HDXRF快速测定土壤中重金属提供理论参考数据。结果表明:HDXRF法测定土壤中Cu、Pb、Zn、Ni、Cd、Cr、As的检出限分别是2mg/kg、2mg/kg、5mg/kg、5mg/kg、0. 08mg/kg、11mg/kg、0. 8mg/kg,满足土壤环境质量标准的测试要求。测定结果与实验室AFS/AAS法测定结果的相关关系系数均在0. 98以上,测定结果具有可比性。HDXRF法测定土壤比实验室分析方法操作简单,无需消解,测定快速,同时可以测定多种元素,无二次污染,可以满足土壤重金属的应急监测需求。

测定土壤和水系沉积物中砷的方法比对研究

便携式X射线荧光光谱法(PXRF)与原子荧光光谱法(AFS)分别对土壤样品和水系沉积物样品进行重金属砷测定的比对实验,两种方法测定结果数据一致性好,相对偏差在-11.8%^+10.9%之间,仪器检出限低。手持式X射线荧光元素分析仪无需复杂的前处理和消解制样过程,近原位快速对重金属砷的测定可达到定量水平。